Bernanke Delves Into Market Puzzle

Unusually low long-term interest rates could require the Fed to keep the short-term rates it controls higher -- or lower -- than normal, Federal Reserve Chairman Ben Bernanke said. It all depends on what is keeping long-term rates down.

Tackling one of the biggest current puzzles in financial markets, Mr. Bernanke turned to a theory he popularized a year ago to suggest that the Fed ought to keep rates lower than it normally would. He...